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Do suggest_await_before_try with infer in self, clean up binders

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This commit is contained in:
Michael Goulet 2022-06-03 18:40:39 -07:00
parent e40d5e83dc
commit d268b34da4
4 changed files with 71 additions and 30 deletions
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48
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -5,7 +5,7 @@ use super::{
use crate::autoderef::Autoderef;
use crate::infer::InferCtxt;
use crate::traits::normalize_projection_type;
use crate::traits::normalize_to;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::stack::ensure_sufficient_stack;
@ -2704,55 +2704,43 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let future_trait = self.tcx.require_lang_item(LangItem::Future, None);
let self_ty = self.resolve_vars_if_possible(trait_pred.self_ty());
// Do not check on infer_types to avoid panic in evaluate_obligation.
if self_ty.has_infer_types() {
return;
}
let self_ty = self.tcx.erase_regions(self_ty);
let impls_future = self.type_implements_trait(
future_trait,
self_ty.skip_binder(),
self.tcx.erase_late_bound_regions(self_ty),
ty::List::empty(),
obligation.param_env,
);
if !impls_future.must_apply_modulo_regions() {
return;
}
let item_def_id = self.tcx.associated_item_def_ids(future_trait)[0];
// `<T as Future>::Output`
let projection_ty = ty::ProjectionTy {
// `T`
substs: self.tcx.mk_substs_trait(
trait_pred.self_ty().skip_binder(),
&self.fresh_substs_for_item(span, item_def_id)[1..],
),
// `Future::Output`
item_def_id,
};
let mut selcx = SelectionContext::new(self);
let mut obligations = vec![];
let normalized_ty = normalize_projection_type(
&mut selcx,
let projection_ty = trait_pred.map_bound(|trait_pred| {
self.tcx.mk_projection(
item_def_id,
// Future::Output has no substs
self.tcx.mk_substs_trait(trait_pred.self_ty(), &[]),
)
});
let projection_ty = normalize_to(
&mut SelectionContext::new(self),
obligation.param_env,
projection_ty,
obligation.cause.clone(),
0,
&mut obligations,
projection_ty,
&mut vec![],
);
debug!(
"suggest_await_before_try: normalized_projection_type {:?}",
self.resolve_vars_if_possible(normalized_ty)
self.resolve_vars_if_possible(projection_ty)
);
let try_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred.map_bound(|trait_pred| (trait_pred, normalized_ty.ty().unwrap())),
trait_pred.map_bound(|trait_pred| (trait_pred, projection_ty.skip_binder())),
);
debug!("suggest_await_before_try: try_trait_obligation {:?}", try_obligation);
if self.predicate_may_hold(&try_obligation)
&& impls_future.must_apply_modulo_regions()
&& let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span)
&& snippet.ends_with('?')
{